of them knows French so I have to ask a fourth person for help.A. NeitherB. EitherC. Bot

问题补充：

of them knows French, so I have to ask a fourth person for help.

A. Neither

B. Either

C. Both

D. None

答案：

A. Neither

B. Either

C. Both

(答案→)D. None

解析：有语句的字面来看，前半句是否定意义，故要问第四个人，表示三者或三者以上的否定用none，故选D.